A decanter centrifuge generally has fixed weir edges and thus a fixed level of the one substance to be discharged (in the following liquid, which is normally the case) in the bowl of the decanter centrifuge. The position of the weir edge is generally determined either by the radial position of the outlet opening in the base plate of the decanter centrifuge, or by the position in which an external weir edge is mounted fixedly on the base plate of the decanter centrifuge, generally such that it covers a part of the outlet opening. Such a decanter centrifuge is e.g. known from JP 11-179236.
Thus the liquid level in the bowl of a known decanter centrifuge is normally determined by the position of the weir edge and cannot be changed, except by unduly complex procedures.
It is one object of the present invention to provide a decanter centrifuge that eliminates or reduces the problem mentioned above.